1. Field of the Invention
The present invention relates in general to embedded software controlled devices. More particularly, the present invention relates to safeguarding the configuration data of programmable radios.
2. Description of Related Art
Currently in the interest of exploiting economies of scale in manufacturing, two way radios that are made for different end use markets and which may use slightly different frequencies, and have different functionality, share a common hardware design, and only differ in so far as configuration settings that are defined in data read by embedded software. In a given locale, one or more user groups (e.g., a police department) may be allocated a portion of spectrum for conducting communication, and be outfitted with two way radios configured to operate securely at frequencies within the allocated spectrum. For many user groups, such as a police department, there is a desire to maintain conversations conducted through two way radios confidential. Unfortunately, the fact that operating frequencies, and other configuration settings, are defined in software, makes it possible for individuals to reprogram such two way radios to change their operating frequency and other configuration settings in order to use those radios to listen to, or send messages using spectrum that the individual is not authorized to use. All that may be required to do so is record information on a Programmable Read Only Memory (PROM) Chip or, on an Electrically Erasable Read Only Memory (EEPROM) Chip. To make large changes in operating frequency some changes to the RF to IF modulator/demodulator hardware may be required.
In a different area of wireless communication, namely cellular telephony, a variety of additional functionality beyond simple voice communication has been introduced. Examples of additional functionality added to cellular communication devices, includes, text messaging, World Wide Web (WWW) surfing, and data exchange. Certain more advanced cellular telephones, are able to communicate using multiple communication protocols. The market for cellular communication devices is stratified according to the level of functionality beyond basic voice telephony and includes devices having a wide range of functionality. It would be desirable to provide a way for users to upgrade the capability of their phones, without having to purchase an entirely new replacement phone.